Since several to tens of unit batteries are typically connected to each other to form one rechargeable battery module, there is a need to efficiently dissipate heat generated from each unit battery. In particular, when the battery module is applied to a hybrid electric vehicle (HEV), efficient heat dissipation is of significant importance.
If the heat dissipation does not occur properly in the battery module, the temperature of the battery module may excessively increase due to the heat generated from each unit battery, and accordingly, not only the battery module but also the machines with the battery module, can malfunction. In the case of prismatic batteries, this problem will become more severe.
Accordingly, when forming the battery module, barriers are disposed between unit batteries, and the space formed by the barriers between unit batteries is used not only for cooling unit batteries but also for preventing distortion due to heat expansion of the unit batteries.
To perform such functions, the barriers need sufficient strength and structure for efficient heat dissipation.
However, the barriers in the conventional battery module do not satisfy the above two conditions simultaneously so there is difficulty in forming battery modules of the quality which consumers expect.
That is, if the barriers ensure the sufficient strength, its manufacturing cost is increased and there are limitations in designing a passage of cooling air. Alternatively, if the barriers are formed having high cooling efficiency, they tend to exhibit structural weakness.